Internally cooled gas turbine vane

ABSTRACT

A gas turbine vane or blade having a novel internal structure that allows for cooling under low pressure ratios. The vane has an air inlet passage that communicates with an inner cooling cavity positioned between the air passage and the vane&#39;s trailing edge. Disposed within this cavity are deflectors, turning members, ribs, and deflecting pins arranged so as to direct the cooling air through the cavity in a manner that minimizes pressure loss. Thus maintaining the velocity and flow of the cooling air.

TECHNICAL FIELD

The present invention relates generally to gas turbine engine nozzles orvanes and turbine blades, and more particularly to the configuration ofthe inner cooling chamber of the vanes and blades.

BACKGROUND ART AND TECHNICAL PROBLEMS

As is known, generally gas turbine engines comprise a compressorsection, a combustion chamber, and a turbine section. In general, thecompressor section draws in air and compresses it. Fuel is then added tothe compressed air in the combustion chamber, and the mixed fluid offuel and compressed air is ignited. The fluid, which is at a temperaturein the range of about 1700-2600 degrees Fahrenheit after ignition, isdirected toward the turbine section where part of the energy in thefluid is extracted by the turbine blades which are mounted to arotatable shaft. The rotating shaft in turn drives a compressor in thecompressor section. The remainder of the energy is used for otherfunctions; for example, the propulsive thrust of a jet aircraft.

To better improve the efficiency of the energy transfer from the fluidto the turbine blades, the angle of attack of the fluid onto the turbineblades is improved by use of non-rotating airfoil shaped fluid nozzlesor vanes. These nozzles or vanes swirl the flow of the hot gas or fluidfrom a nearly parallel flow with the blades to a generallycircumferential flow onto the blades. Because the combusted fluid is ata very high temperature when it comes in contact with the vane, the vanemust be designed to withstand high temperatures for long periods oftime.

Conventional gas turbine nozzles or vanes are generally internallycooled by pumping a portion of the compressed air through an internalcooling cavity in the vane. However, the cooling cavities currentlyknown in the art are designed for high pressure drop, high velocity airflow systems and will not effectively cool nozzles used in low pressureratio engines. For example, most vanes are designed to operate inmachines that have a differential pressure of about 40-80 psi. Examplesof the conventional prior art include U.S. Pat. Nos. 3,574,481 to PyneJr. entitled "Variable Area Cooled Airfoil Construction for GasTurbines," 4,105,364 to Dodd entitled "Vane for a Gas Turbine EngineHaving Means for Impingement Cooling Thereof," 4,278,400 to Yamarik etal. entitled "Coolable Rotor Blade," 4,403,917 to Laffitte et al.entitled "Turbine Distributor Vane," 4,456,428 to Cuvillier entitled"Apparatus for Cooling Turbine Blades," 4,515,523 to North et al.entitled "Cooling Arrangement for Airfoil Stator Vane Trailing Edge,"5,288,207 to Linask entitled "Internally Cooled Turbine Airfoil,"5,337,805 to Green et al. entitled "Airfoil Core Trailing Edge Region,"and 5,342,172 to Coudray et al. entitled "Cooled Turbo-Machine Vane."

As will be appreciated, there thus exists a need for a turbine vane thatcan be internally cooled when used in a low pressure ratio engine; forexample, about a 3 psi pressure differential.

SUMMARY OF THE INVENTION

A gas turbine vane or blade according to the present invention addressesmany of the shortcomings of the prior art.

In accordance with one aspect of the present invention, a turbine vanecomprises an air inlet opening located at a first side of the vane, afirst air passage extending along a leading edge from the first side toa second side, wherein the first air passage communicates with the airinlet opening, and an inner cooling cavity positioned between the firstair passage and a trailing edge and separated from the first air passageby a divider. In accordance with this aspect of the invention, the innercooling cavity comprises first, second and third channel deflectors,each of which extend from the trailing edge of the vane. The innercooling cavity further comprises first and second outer turning membersand first and second inner turning members positioned within the innercooling cavity.

In accordance with another aspect of the present invention, the gasturbine vane includes a rib extending from an inner wall of the firstair passage in a helical pattern.

In accordance with yet another aspect of the present invention, theinner cooling cavity of the gas turbine vane includes a plurality of airdeflecting pins positioned throughout the cavity.

In accordance with still another aspect of the present invention, theinner walls of the first and second sides, the channel deflectors andthe turning members include at least one half pin.

In accordance with yet another aspect of the present invention, theinner walls of the first and second sides and the channel deflectorsform a series of air channels, each air channel comprising at least oneair flow separator extending from the trailing edge of the vane. The airchannels may comprise at least one rib, and the channel deflectors maybe hook-shaped.

In yet another aspect of the present invention, the same air passage andcooling cavity design is used for gas turbine blades.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Preferred exemplary embodiments of the present invention will hereafterbe described in conjunction with the appended drawing figures, whereinlike designations denote like elements, and:

FIG. 1 shows the inner cooling area of a gas turbine vane which embodiesan embodiment of the present invention;

FIG. 2 shows a portion of the inner cooling cavity of FIG. 1 enlarged todepict with greater clarity the inner air passage and the shape andconfiguration of the channel deflectors and turning members;

FIG. 3 shows an enlarged portion of the inner cooling cavity of FIG. 1,highlighting the shape and configuration of the first tube and the radiiof the inner turning members; and

FIG. 4 shows the gas turbine vane of FIG. 1 highlighting the locationand configuration of the air deflecting pins.

DETAILED DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

The present invention generally relates to internally cooled gas turbinenozzles or vanes as well as internally cooled turbine blades. However,the preferred exemplary embodiment discussed herein relates to oneembodiment of a nozzle or vane.

Referring now to FIG. 1, a vane 10 of the present invention generally iscooled by pumping a fluid, relatively cooler than the gas flowing acrossthe surfaces of the vane 10, into cooling passages formed on the insideof vane 10. In accordance with various embodiments of the presentinvention, the particular configuration of the cooling passages in vane10 force air to evenly circulate throughout the entire cooling passagethereby evenly cooling the entire vane which may be used in both low andhigh pressure ratio engines.

Now describing vane 10 in more detail, vane 10 preferably comprises aleading edge 12, a trailing edge 14, a first side 16, a second side 18,a first air passage 20, and an inner cooling cavity 30.

First air passage 20 is located adjacent to and extends along leadingedge 12 from first side 16 to second side 18. One end of air passage 20communicates with and opens into an air inlet opening 24 located atfirst side 16, whereas the other end of air passage 20 communicates withsecond side 18 at an opening 22. As can be appreciated by one skilled inthe art, as air or fluid passes through first air passage 20 from airinlet opening 24 to opening 22, leading edge 12 is cooled.

In a preferred exemplary embodiment of the present invention, airpassage 20 may have an effective diameter in the range of about 0.04inches to about 0.3 inches, depending on the size of the vane 10. Inaddition, as shown in FIG. 1, in a preferred embodiment of the presentinvention, the end of air passage 20 that communicates with second side18 may flare out. More particularly, as shown by angles A and B, theangle of taper of air passage 20 may be in the range of about 2.75 to4.25 degrees.

Preferably, first air passage 20 includes a rib or turbulator 28extending from the inner wall of passage 20 in a generally helicalpattern. Rib 28 suitably disrupts the boundary layer of the air or fluidas it passes through first air passage 20 allowing the fluid to moreadequately cool leading edge 12. In accordance with one aspect of thepreferred embodiment of the present invention, rib 28 may have a widthin the range of about 0.01 to about 0.02 inches and preferably about0.015 inches. Similarly, the height of rib 28 may be in the range ofabout 0.005 to about 0.015 inches and preferably about 0.010 inches.Nevertheless, as one skilled in the art can appreciate, rib 28 may beany size and pattern suitable for adequately cooling air passage 20, andin some cases, may be omitted.

With continued reference to FIG. 1, inner cooling cavity 30 is suitablyoriented between first air passage 20 and trailing edge 14, and airpassage 20 and cavity 30 are preferably separated by a divider 26. Asair or fluid enters into air inlet opening 24, divider 26 suitablycauses a portion of the air or fluid to pass into first air passage 20,and an other portion to pass into cavity 30 via an inner air passage 32.

In general, cavity 30, as disclosed herein, comprises a plurality of airchannels defined by respective deflectors and includes respectiveturning members and strategically located air deflecting pins. Inparticular, in accordance with a preferred exemplary embodiment of thepresent invention, air passage 32 communicates with and feeds aplurality of air channels 38, 50, 58, and 66.

First air channel 38 is formed between first side 16 and a generallyhook-shaped first channel deflector 40. Preferably, deflector 40 spansfrom air passage 32 to trailing edge 14. Positioned between side 16 anddeflector 40 and in fluid communication with air passage 32 is a firstouter turning member 42 suitably configured to deflect and direct theair or fluid as it enters channel 38, thereby maintaining the fluid'svelocity and pressure as it passes into and through channel 38.

Second air channel 50 is formed between deflector 40 and a secondchannel deflector 52. Preferably, deflector 52 evidences a configurationsimilar to deflector 40. Positioned between deflectors 40 and 52 and influid communication with air passage 32 is a first inner turning member54 suitably configured to direct the fluid flow. In accordance withsimilar configurations, third air channel 58 is formed between deflector52 and a similarly configured third channel deflector 60, and fourth airchannel 66 is positioned between deflector 60 and second side 18. Bothin fluid communication with air passage 32 and suitably configured todirect fluid flow, a second inner turning member 62 is positionedbetween deflectors 52 and 60, and a second outer turning member 68 ispositioned between deflector 66 and side 18.

In a preferred exemplary embodiment of the invention, as air passage 32extends along divider 26 from air channel 38 to air channel 66, itpreferably tapers inward, thereby maintaining the pressure and velocityof the fluid as it flows from inlet opening 24 to air channel 66. Thatis, air passage 32 may be suitably configured such that the effectivediameter of air passage 32 where it communicates with air inlet opening24 is greater than its effective diameter where it communicates with airchannel 66, thereby defining a centerline 31 through the air passage 32that is disposed from the divide 26 by an angle in the range of 2 to 5degrees. In a preferred exemplary embodiment of the present invention,the equivalent diameter of air passage 32 at opening 24 is preferably inthe range of about 0.05 inches to about 0.5 inches depending on the sizeof the vane. Similarly, the equivalent diameter of air passage 32between divider 26 and outer turning member 68 is in the range of about0.05 inches to about 0.15 inches.

Still referring to FIG. 1, in accordance with a further aspect of apreferred embodiment of the invention, air channels 38, 50, 58 and 66may include at least one air flow separator extending from trailing edge14 toward leading 12. In a preferred embodiment of the invention, firstchannel 38 may suitably include flow separators 44 and 48, secondchannel 50 may include flow separator 56, third channel 58 may includeflow separator 64, and fourth channel 66 may include flow separator 70.Further, channels 38, 50, 58 and 66 may include a plurality of ribs 46that generally extend from an inner wall of cavity 30 partially into thecavity and, preferably, are positioned at trailing edge 14 between theflow separators, channel deflectors, and first and second sides 16, 18.It should be noted that to reduce the cost of producing the vane, it maybe desirable to produce the vane without the various flow separators andribs. Therefore, a preferred embodiment of the invention may exclude theflow separators and/or ribs located at the trailing edge.

Still, referring to FIG. 1, in accordance with a preferred exemplaryembodiment of the present invention, channel deflectors 40, 52 and 60,and turning members 42, 54, 62 and 68 are generally arcuate orhook-shaped and are suitably defined by a plurality of angles shown inFIG. 1 as angles C-N and described in more detail below.

In particular, in accordance with a preferred embodiment, the leadingedges of turning members 42, 54, 62 and 68, and channel deflectors 40,52 and 60, all of which communicate with air passage 32, preferablycurve toward air inlet opening 24, creating angled air tubes 100, 102,104, 110 and 116. The angles at which these tubes communicate with airpassage 32 help dictate the volume and the velocity of the air thatpasses into each channel. The relative angles of the tubes with respectto passage 32 are measured as the angle created between the centerlineof each tube and the centerline 31 of air passage 32. These angles areillustrated in FIG. 1 as angles C, E, G, J and M and are generally inthe range of about 20 to about 45 degrees.

More particularly, tube 100 is suitably formed between side 16 andturning member 42 and evidences an angle C with respect to air passage32, generally in the range of about 32 to about 42 degrees andpreferably about 36 degrees. Further, tube 102 is formed between turningmember 42 and deflector 40 and preferably evidences an angle E, which isgenerally in the range of about 33 to about 43 degrees and preferablyabout 37.7 degrees. Tube 104 is suitably formed between deflector 40 andthe leading edge of deflector 52 and defines an angle G with respect tocenterline 31 which is generally in the range of about 22 to about 32degrees and preferably about 27.6 degrees. Tube 110 is formed betweendeflector 52 and the leading edge of deflector 60 and forms angle J withrespect to centerline 31. Preferably, angle J is in the range of about24 to about 34 degrees and more preferably about 28.9 degrees. Finally,tube 116 is formed between deflector 60 and turning member 68 and formsan angle M with respect to centerline 31, which is generally in therange of about 25 to about 35 degrees and preferably about 0.3 degrees.

As illustrated in FIG. 1, tubes 100-116 generally curve as they traversefrom air passage 32 into their respective air channels 38, 50, 58 and66. The configuration of the tubes allows for turning of the fluidwithout substantial loss of pressure head and velocity. As one skilledin the art can appreciate, the angle of the tubes with respect tocenterline 31 and the generally curved configurations of the tubes allowthe air passing through the vane to turn from air passage 32 into theair channels at a high velocity. This is an improvement over the priorart vanes which require orifices with much lower pressure losses as airflow passes through the vane.

Therefore, as one skilled in the art can appreciate, the generallycurved configuration of tubes 100-116 may be important. In a preferredembodiment of the invention, tubes 100-116 are suitably defined by therelative relationship of the turning members and channel deflectors withrespect to one another and preferably evidence angles in the range ofabout 100 to about 170 degrees. In particular, the angles of tubes100-116 are defined as the relative angles created by the intersectionof the center lines of the tubes. For example, as illustrated in FIG. 1,center lines 100a and 100b are the center lines of the first and secondportions of tube 100 respectively. The angle of tube 100 is measured asthe relative angle of center lines 100a and 100b.

Referring now to each specific tube 100-116, tube 100 is formed betweenfirst side 16 and first outer turning member 42. As tube 100 extendsfrom air passage 32 to channel 38, it curves, thus evidencing an angleD. Preferably, angle D is in the range of about 100 to about 160 degreesand more preferably about 141.2 degrees. Preferably, tubes 102, 104,106, 110, 112 and 116 evidence similar curved or angled configurations.The angled orientation of tubes 102, 104, 106, 110, 112 and 116 aresuitably defined by angles F, H, K and N respectively and are enumeratedas follows: angle F is generally in the range of about 100 to about 160degrees, and preferably about 130.6 degrees; angle H is generally in therange of about 100 to about 160 degrees and preferably about 127.9degrees; angle K is generally in the range of about 100 to about 160degrees and preferably about 121 degrees; and angle N is generally inthe range of about 100 to about 160 degrees and preferably about 120.3degrees.

In accordance with a further aspect of a preferred embodiment, air flowtube 104 divides at first inner turning member 54, creating tubes 106and 108. In particular, tube 106 is suitably formed between channeldeflector 40 and turning member 54, and tube 106 is suitably formedbetween turning member 54 and channel deflector 52. Tube 104 and 108communicate with each other, forming an angle I at the communicationpoint. In a preferred embodiment, angle 1 is generally in the range ofabout 25 to about 45 degrees, and more preferably about 29.5 degrees.Similarly, tube 110 divides at second inner turning member 62 to formtubes 112 and 114. Tube 112 is suitably formed between deflector 52 andturning member 62, and tube 114 is suitably formed between turningmember 62 and deflector 60. The communication of tubes 110 and 114 formsan angle L which is preferably in the range of about 25 to about 45degrees and more preferably about 36.8 degrees.

In accordance with a further aspect of a preferred embodiment of theinvention, channel deflectors 40, 52, and 60 are suitably positionedsuch that channels 38, 50, 58, and 66 comprise specific percentages ofthe overall inner cooling cavity 30. Preferably, first channel deflector40 is positioned such that first air channel 38 comprises about 20 toabout 50 percent of cavity 30, and more preferably about 30 percent.Similarly, second channel deflector 52 is positioned relative todeflectors 40 and 60 such that second air channel 50 preferablycomprises about 20 to about 50 percent of cavity 30, and more preferablyabout 25 percent. In the same manner, third air channel 58 preferablycomprises about 20 to about 50 percent of cavity 30, and more preferablyabout 25 percent, and fourth channel 66 preferably comprises about 20 toabout 50 percent, and more preferably about 30.

During operation of the turbine engine, cool air will first flow intoair inlet 24. The particular contour and shape of air inlet 24 helpsstabilize the air flow as it passes into first air passage 20 and secondair passage 32. Referring now to FIG. 2, the radius R1 of inlet 24,which connects the mouth 118 of inlet 24 to the neck 119 of inlet 24,generally will help promote stable flow of the air as it enters airpassages 20 and 32. In a preferred embodiment of the invention, R1 maybe in the range of about 0.04 to about 0.25 inches, and preferably aslarge as possible. In addition, to also help stabilize the air as itenters air passages 20 and 32, the length of inlet neck 119 (L1 in FIG.2) is preferably as long as possible. In a preferred embodiment of thepresent invention, L1 will be at least twice the size of the relativediameter of air passage 32 (d1 in FIG. 2).

As air flows through neck 119 into second air passage 32, a portion ofthe air will flow through tubes 100 and 102 into first air channel 38.The size of tubes 100 and 102, the angle at which they are located withrespect to air passage 32, and the radius R2 of first side 16 shouldhelp control the amount of air that flows through the tubes. Asdiscussed above, the angle of tubes 100 and 102 with respect to airpassage 32 is preferably in the range of about 20 to about 45 degrees.

Still referring to FIG. 2, radius R2 is formed on the inner wall offirst side 16 and forms the top of tube 100. If radius R2 is too small,the entry of air into tube 100 will be disrupted, and first channel 38will not be properly cooled. Similarly, if radius R2 is too large, toomuch air will flow through tube 100, taking air away from the other airchannels. In a preferred embodiment of the invention, radius R2preferably is in the range of about 0.100 to about 0.250 inches and morepreferably about 0.180 inches.

The length of tube 100 is also a factor controlling the flow of airthrough the tube. Referring now to FIG. 3, in a preferred embodiment ofthe invention, the length L5 of tube 100 will preferably be at leasttwice the width W5 of tube 100. Therefore, length L5 will be in therange of about 0.04 to about 0.10 inches and preferably about 0.08inches.

Now referring back to FIG. 2, the size of the radii R3-R7 of the leadingedges of the turning members and channel deflectors also are factors incontrolling the air flow into each of the tubes. To ensure that thelength of tubes 100, 102, 104, 110 and 116 are as large as possible,radii R3-R7 will preferably be as small as possible. Due tomanufacturing constraints, radii R3-R7 preferably will be in the rangeof about 0.010 to about 0.015 inches and more preferably about 0.012inches.

Referring now to second channel 50 and third channel 58, air or fluidwill enter channels 50 and 58 from air passage 32 through tubes 104 and110 respectively. As the air or fluid flows through tubes 104 and 110,it will collide with turning members 54 and 62 respectively, causing thefluid to separate. The fluid entering tube 104 will divide equally intotubes 106 and 108, and the fluid entering tube 110 will divide intotubes 112 and 114; alternatively, the tubes can be sized so that thesplit in flow is not equal. For proper fluid flow from air passage 32through tubes 104 and 110 into channel 50 and 58, turning members 54 and62 should be properly aligned within the channels. In a preferredembodiment of the invention, the width of the leading edges 120 and 122of turning members 54 and 62 should be slightly wider than tubes 104 and110 respectively. Moreover, for fluid to separate equally into tubes 106and 108, and 112 and 114, leading edges 120 and 122 should be centeredalong tubes 104 and 110 respectively.

For proper fluid distribution into tube 106, 108, and 112, 114, radiusR8 of turning member 54, radius R10 of deflector 40 and radius R11 ofdeflector 52 will preferably be symmetrical about the centerline of tube104 (see FIG.3). That is, if radii R8, R10 and R11 are extended out,they will all intersect at the centerline of tube 104. Preferably, radiiR9, R12 and R13 of turning member 62 and deflectors 52 and 60respectively will be similarly symmetrical about the centerline of tube110.

Finally, the widths of tubes 106, 108, 112 and 114 help control theamount of fluid that enters into channels 50 and 58. Referring back toFIG. 2, the opening of tube 106 is suitably formed between the leadingedge 120 of turning member 54 and the lower corner 128 of first channeldeflector 40. The width of this opening is illustrated in FIG. 2 as W1.Similarly, the opening of tube 108 is suitably formed between leadingedge 120 and first upper corner 130 of second channel deflector 52 andis shown as W2 in FIG. 2. The openings of tubes 112 and 114 are suitablyformed between turning member 62 and corners 132 and 134 of channeldeflectors 52 and 60 respectively with the widths being shown as W3 andW4. In a preferred embodiment of the present invention, widths W1-W4 ofthe tubes 106, 108, 112 and 114 preferably will be based on velocitiesrequired to cool the passage. In the preferred embodiment, widths W1-W4will be in the range of about 0.01 to about 0.05 inches and morepreferably about 0.03 inches.

As air flows out of tubes 106 and 108 into second air channel 50, andout of tubes 112 and 114 into third air channel 58, the air dispersesthroughout channels 50 and 58. To ensure even air coverage of the aftportions the channels 50 and 58, the aft ends 124 and 126 of turningmembers 54 and 62 are suitably positioned at the center of channels 50and 58 to properly direct the air to all parts of each channel. That is,aft end 124 of turning member 54 is generally centered between firstchannel deflector 40 and second channel deflector 52, and aft end 126 ofturning member 62 is generally centered between second channel deflector52 and third channel deflector 60.

Referring now to FIG. 4, as air or fluid flows through second airpassage 32, portions of the air separate out and flow into the variousair channels. As the amount of air in passage 32 decreases, the airvelocity will also decrease. To help maintain the proper velocitythroughout the entire inner cavity 30, air passage 32 tapers down fromthe inlet to the exit end of the passage. In addition, to help maintainvelocity and ensure the proper amount of air flow into each channel, theleading edge of second channel deflector 52 is angled such that if theleading edge is extended back, it would overlap the leading edge ofthird channel deflector 60 (see 140 in FIG. 4). In a similar manner, theleading edge of channel deflector 60 is angled such that it wouldoverlap second outer turning member 68.

In addition to the channel deflectors and turning members, inner cavity30 may contain a plurality of air deflecting pins 142 and half pins 144suitably configured to direct the air as it flows through cavity 30.Pins 142 are suitably sized and positioned in each channel to direct andseparate the cooling flow within each channel. In a preferred embodimentof the present invention, the spacing between pins 142 from center tocenter (L2 in FIG. 4) preferably is in the range of about 1.5 to about 5diameters of the pins 142 and more preferably about 2.5 diameters. Inaccordance with a further aspect of the present invention, the spacingfrom the edge of pins 142 to the inner walls, turning members, andchannel deflectors (L3 in FIG. 4) is preferably in the range of about1.5 to about 5 pin diameters and more preferably about 2.5 pindiameters. It should be noted that some of the pins may not meet the pinspacing specifications enumerated above. For example, in the preferredembodiment, pins 146-156, do not meet the pin spacing specifications.Moreover, it should be noted that pins 142 may be placed at any and alllocations within cavity 30 necessary to obtain proper flow distribution,or pins 142 may be randomly placed in cavity 30.

Half pins 144 extend from the inner walls of first and second sides 16,18 and from the various turning members and channel deflectors and areconfigured to direct the air as it flows through the various channels.In a preferred embodiment of the invention, half pins 144 preferably maybe placed at any location on the walls, turning members, and channeldeflectors necessary to properly direct the air flow within the airchannels.

It will be understood that the foregoing description is of preferredexemplary embodiment of the invention, and that all dimensions are givenfor the preferred embodiment. One skilled in the art should appreciatethat the dimensions may vary in other embodiments of the invention. Inparticular, as the overall size of the vane varies the inner dimensionsof the vane will vary accordingly. Moreover, the invention is notlimited to the specific forms shown herein. Various modifications may bemade in the design and arrangement of the elements set forth hereinwithout departing from the scope of the invention as expressed in theappended claims.

We claim:
 1. A turbine distributor vane comprising:an air inlet openingpositioned at a first side of the vane; a first air passage extendingalong a leading edge from the first side to a second side, wherein thefirst air passage communicates with the air inlet opening and terminatesat an opening at the second side; andan inner cooling cavity positionedbetween the first air passage and a trailing edge and separated from thefirst air passage by a divider, wherein the inner cooling cavitycomprises; a first channel deflector, a second channel deflector and athird channel deflector, each of which extend through the inner coolingcavity from the trailing edge toward the divider separating the firstair passage from the inner cooling cavity; a first outer turning memberpositioned between an inner wall of the first side and the first channeldeflector; a first inner turning member positioned between the firstchannel deflector and the second channel deflector; a second innerturning member positioned between the second channel deflector and thethird channel deflector; a second outer turning member positionedbetween the third channel deflector and an inner wall of the secondside.
 2. The turbine vane of claim 1, wherein the first air passageincludes a rib extending from an inner wall of the air passage in ahelical pattern.
 3. The turbine vane of claim 1, wherein the innercooling cavity includes a plurality of pins positioned throughout thecavity.
 4. The turbine vane of claim 1, wherein the inner wall of thefirst side, the inner wall of the second side, the first channeldeflector, the second channel deflector and the third channel deflectoreach comprise at least one half pin.
 5. The turbine vane of claim 4,wherein the first outer turning member, the second outer turning member,the first inner turning member and the second inner turning member eachcomprise at least one half pin.
 6. The turbine vane of claim 1, whereinthe inner wall of the first side, the first channel deflector, thesecond channel deflector, the third channel deflector and the inner wallof the second side form a series of air channels, each air channelcomprising at least one air flow separator extending from the trailingedge of the vane.
 7. The turbine vane of claim 1, wherein the airchannels comprise at least one rib extending from the trailing edge ofthe vane.
 8. The turbine vane of claim 1, wherein the first channeldeflector, the second channel deflector and the third channel deflectorare hook-shaped.
 9. A turbine blade comprising:an air inlet openingpositioned at a first side of the blade; a first air passage extendingalong a leading edge from the first side to a second side, wherein thefirst air passage communicates with the air inlet opening and terminatesat an opening at the second side; and an inner cooling cavity positionedbetween the first air passage and a trailing edge and separated from thefirst air passage by a divider, wherein the inner cooling cavitycomprises;a first channel deflector, a second channel deflector and athird channel deflector, each of which extend through the inner coolingcavity from the trailing edge toward the divider separating the firstair passage from the inner cooling cavity; a first outer turning memberpositioned between an inner wall of the first side and the first channeldeflector; a first inner turning member positioned between the firstchannel deflector and the second channel deflector; a second innerturning member positioned between the second channel deflector and thethird channel deflector; a second outer turning member positionedbetween the third channel deflector and an inner wall of the secondside.
 10. The turbine blade of claim 9, wherein the first air passageincludes a rib extending from an inner wall of the air passage in ahelical pattern.
 11. The turbine blade of claim 9, wherein the innercooling cavity includes a plurality of pins positioned throughout thecavity.
 12. The turbine blade of claim 9, wherein the inner wall of thefirst side, the inner wall of the second side, the first channeldeflector, the second channel deflector and the third channel deflectoreach comprise at least one half pin.
 13. The turbine blade of claim 12,wherein the first outer turning member, the second outer turning member,the first inner turning member and the second inner turning member eachcomprise at least one half pin.
 14. The turbine blade of claim 9,wherein the inner wall of the first side, the first channel deflector,the second channel deflector, the third channel deflector and the innerwall of the second side form a series of air channels, each air channelcomprising at least one air flow separator extending from the trailingedge of the blade.
 15. The turbine blade of claim 9, wherein the airchannels comprise at least one rib extending from the trailing edge ofthe blade.
 16. The turbine blade of claim 9, wherein the first channeldeflector, the second channel deflector and the third channel deflectorare hook-shaped.
 17. A turbine airfoil comprising:an air inlet openingpositioned at a first side of the airfoil; a first air passage extendingalong a leading edge from the first side to a second side, wherein thefirst air passage communicates with the air inlet opening; and an innercooling cavity positioned between the first air passage and a trailingedge and separated from the first air passage by a divider, wherein theinner cooling cavity comprises;a channel deflector extending through theinner cooling cavity from the trailing edge toward the dividerseparating the first air passage from the inner cooling cavity; a firstouter turning member positioned between an inner wall of the first sideand the channel deflector; a first inner turning member positionedbetween the channel deflector and an inner wall of the second side.